1. Field of the Invention
The present invention relates to engine control systems, which are capable of switching a valve opening parameter from a first value to a second value. The valve opening parameter means an opening of a valve to be used in an engine for controlling the flow of a fluid through the valve.
For example, as one of the valve opening parameters, a valve lift defined as a physical distance from a valve to a corresponding seat, a valve opening timing, a valve opening period, or the like can be used.
2. Description of the Related Art
There are some of conventional internal combustion engines that are configured to switch, in response to an external switching request, from a predetermined first lift of at least one intake or exhaust valve to a predetermined second lift thereof; this at least one intake or exhaust valve has been installed in each cylinder of the internal combustion engines.
Because at least one control parameter required for a control unit to control an internal combustion engine depend on the first lift of the at least one intake or exhaust valve, it is necessary for the control unit to correct the at least one control parameter at proper timing to meet the second lift.